虾和鲑鱼种植：对当地经济的影响

Introduction

The alarming increase of world population, expected to be 7.5 billion by 2017, has imposed a pressure on food production and security. A grave concern in this line is the adequate feeding to each individual both in the developed and developing countries. Oceans had been an excellent source of fish food, fulfilling the needs of millions of communities until the fish stocks declined at steady rate. In order to maintain a continuous supply of sea foods, between 1987 and 1997, a rapid growth of farming fish or aquaculture was implemented which grabbed a significant portion in the world fish supplies (FAO, 1999). Although aquaculture is meeting the fish protein need of more than half of the world population, however, environmental and ecological issues are often debatable. Aquaculture of these species undoubtedly enhanced the living status of local communities with job opportunities but some of the inevitable issues include habitat destruction, disease transmission, eutrophication and decrease of wild species which makes the industry economically unreliable for local communities in long run.

虾养殖的经济影响

尽管虾类水产养殖是一种有利可图的方法，但强化农业是此类行业的丑陋一面。密集型虾养殖的最具破坏性的影响之一是破坏红树林生态系统，通常被选为池塘设施，但是以破坏红树林生态系统服务为代价，包括托儿所栖息地，沿海保护，洪水控制，洪水控制，沉积物，沉积物捕获和水处理。在东南亚，从1970年代后期，有250万到375万英亩的各种类型的湿地和红树林被降落用于虾类。依靠水和红树林生态系统捕鱼的当地社区的生活也受到生动影响。为水产养殖设置池塘设施包括引入海水，从而增加土壤的盐度。有报道称，由于土壤盐分，附近的水稻农场产量降低了。在越南的湄公河三角洲，大部分水产养殖都已经完成，盐水引入了盐水妨碍农业的淡水供应约30,000公顷，最终极大地限制了大米的生产（Tran，1994）。此外，在水产养殖耕作中疾病爆发，然后大量使用化学物质和抗生素作为治疗措施，使土壤不适合农业，由于高盐度而无法恢复，因此土地被标记为废弃（World Bank等，2002）。疾病爆发还会导致该行业的经济损失，这可能会使当地人失业，否则他们可能会通过钓鱼和农业过上和平的生活。

Economical impact of salmon farming

It is clear that farmed salmons are a threat to commercial salmon fishing. Salmon farming is another harmful aquaculture practices. Farmed salmon are maintained in open net-cages placed in the ocean resulting in the contamination of ocean due to waste excretion, chemicals, as well as disease outbreaks killing the wild species. Salmon being carnivore requires a large portion of wild fishes for food and this in turn depleting the wild fish stocks. Another detrimental effect of salmon farming is the transmission of sea lice, which easily proliferates in salmon farms, to juvenile wild salmon. About 80% of mortality was evidenced among wild juvenile pink salmon (Oncorhynchus gorbuscha）在加拿大太平洋海岸，是由于养殖鲑鱼从养殖鲑鱼传播的结果（Krkosek等，2007）。此外，文献引用了有时养殖的鲑鱼从海笼逃离开放海洋环境，在那里它们与野生物种杂交，从而使后代降低了遗传多样性，短期寿命，并且对疾病极易受到影响（Gardnerand and Peterson，2003; Thorstad等； Thorstad等人，等等，2008）。由于上述所有因素，野生鲑鱼数量减少，直接影响当地社区的经济。

尽管对经济产生了负面影响，但考虑到水产养殖业带来的工作机会，人们发现了积极的射线。当地人是通过为可持续有机农业提供必要的培训来雇用的，从而满足了他们的人力要求。人民从生活源中受益。在戈尔韦湾（Galway Bay）的深海项目下，约有350人提供工作。在爱尔兰水产养殖业提供了1000多人的工作。但是，由于养殖鲑鱼的疾病突然爆发，此类工作的可靠性令人怀疑。

Conclusion

确实，虾和鲑鱼水产养殖有一些积极的方面，其中包括向沿海地区当地社区的收入以及减少野生储备捕鱼的可用性。但是，采用的密集农业来满足不断增长的需求，具有毁灭性的影响，包括由于人口过多而引起的疾病暴发，这可能会影响野生物种，导致遗传多样性的丧失。由于红树林的破坏而损失饮用水给当地社区，并破坏便携式水源会严重影响当地社区的经济。适应可持续水产养殖实践和资源管理将是减少此类问题的强大解决方案。